That looks a fair bit like my hair when I just don't care about doing anything with it for a couple of days. Or, after I've worn it in a braid/tightly twisted bun and let it out and can't stop touching it. These days it looks far better in general....

So, for me, I've cut my hair short 2 or 3 times I think, short meaning around that length. While getting all the weight off was wonderful, I grew it out straight away because it was so annoying to deal with. I get triangle hair big time. It gets huge, braiding it down or do anything to reduce volume is hard. The extra weight of longer hair pulls my hair down and makes it a lot more managable. Remove that weight and it springs up. (Disclaimer, I didn't know how to handle my curls back then so I brushed it. Made it worse so it might not have been quite as bad if I'd treated it as curly hair).

So, if you plan for that length I would suggest considering see if you need layering, which while it can make your hair bigger, as it would make the upper layers wpring even more it might remove a fair bit of the triangle-ness. At the same time it would be hard to get the shorter layers out of your face... What might be a better idea is to look at photos of those with your curl pattern and density with a similar length and consider photos of that. It will probably give you a better idea of what you can expect as I'm guessing that even straightened you hair will have more volume than it that photo... :/

If you want to cut it short, definitely go for it! I know I've sounded very negative now, but it is really nice to be able to let go of all of that weight and not have your hair get caught in every top you put on. It feels different in a good way. Plus it's hair, it will always grow out.